The attachment of intravenous tubing to intravascular catheters for the administration of fluids and/or medication to patients has been widely utilized for over three decades. Generally, an intravenous tubing system comprises a long segment of tubing which is proximally attached to an elevated bag or bottle of fluid and distally attached to an intravascular catheter. Such a system acts as a primary system, and a secondary conduit may be connected to the primary system. To allow for such connection, such primary systems often have a "y" shaped branch junction section with a penetrable self-sealing septum. A needle attached to the end of the second conduit can be inserted through such a septum to create fluid connection between the primary system and second conduit. Thus, the septum provides a mechanism for the recurrent and frequent connection of secondary, "piggyback" intravenous tubing systems to the primary tubing system. Such second or piggyback systems typically include a small bag of antibiotic or other medication which is dissolved in a fluid and connected to a long flexible plastic conduit. The intermittent connections of such secondary intravenous systems to the primary system allows the administration of the medication at frequent intervals without disconnecting the primary intravenous system and without discontinuing fluid flow through the primary system.
Such "y" shaped tubes typically have a tubular trunk with a cylindrical tubular arm branching from it at an angle which can range from about 30.degree. to 45.degree. . The longitudinal section through such an arm is of elliptical shape. The major axis of this elliptical section varies with the angle of extension of the arm. In particular, the major axis length increases as the angle of arm extension decreases.
A major problem with such systems is that the needles frequently loosen and become disconnected from the septum during fluid administration. This can result in the medication spilling into the patient's bed or on the floor. An even greater problem is that the needle may become contaminated during disconnection. The contaminated needle portion may be readvanced through the septum, thereby introducing contamination into the primary tubing system.
U.S. Pat. No. 4,752,292 discloses a device which helps prevent disconnection of a needle from a compatible interfacing tube having a septum. However, application of this device is limited to tubing systems with specifically compatible interfacing components which fit together. Therefore, the use of that disclosure would require structural changes to the conventional tubing systems which contain septae, and which are deployed in a wide range of existing tubing systems and have long been in use with heterogeneous populations of infusion pumping mechanisms and other devices.